Design of a controlled spatial curve trajectory for robot manipulators

The authors present a two-phase robot trajectory planning method that decomposes trajectory planning into path-geometry planning and robot-movement-speed planning. The purpose is to provide a capability for varying the speed of robot motion without changing the geometric shape of the path itself. A modified cubic spline method is applied to plan various spatial paths for robot´s trajectory. It is concluded that the approach generates a more versatile trajectory for robot manipulators and that it maintains the smoothness of robot motion along any twisted spatial path. The proposed trajectory planner is simulated for several examples that elucidate the major issues